85 (number)

85 (eighty-five) is the natural number following 84 and preceding 86.

← 84 85 86 →
← 80 81 82 83 84 85 86 87 88 89 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	eighty-five
Ordinal	85th (eighty-fifth)
Factorization	5 × 17
Divisors	1, 5, 17, 85
Greek numeral	ΠΕ´
Roman numeral	LXXXV
Binary	10101012
Ternary	100113
Senary	2216
Octal	1258
Duodecimal	7112
Hexadecimal	5516

In mathematics

85 is:

• the product of two prime numbers (5 and 17), and is therefore a semiprime of the form (5.q) where q is prime.
• specifically, the 24th Semiprime, it being the fourth of the form (5.q).
• together with 86 and 87, forms the second cluster of three consecutive semiprimes; the first comprising 33, 34, 35. ^[1]
• with a prime aliquot sum of 23 in the short aliquot sequence (85,23,1,0).
• an octahedral number. ^[2]
• a centered triangular number. ^[3]
• a centered square number. ^[4]
• a decagonal number. ^[5]
• the smallest number that can be expressed as a sum of two squares, with all squares greater than 1, in two ways, 85 = 9² + 2² = 7² + 6². ^[6]
• the length of the hypotenuse of four Pythagorean triangles.
• a Smith number in decimal. ^[7]
• in binary is 1010101 (64 + 16 + 4 + 1)

In astronomy

• Messier object M85 is a magnitude 10.5 lenticular galaxy in the constellation Coma Berenices
• NGC 85 is a galaxy in the constellation Andromeda
• 85 Io is a large main belt asteroid
• 85 Pegasi is a multiple star system in constellation of Pegasus
• 85 Ceti is a variable star in the constellation of Cetus
• 85D/Boethin is a periodic comet

In titles and names

• Federalist No. 85 , by Alexander Hamilton, the last of The Federalist Papers (1788)
• The 85 Ways to Tie a Tie , a book by Thomas Fink and Yong Mao
• 85 Days: The Last Campaign of Robert Kennedy, a book by Jules Witcover
• Live/1975–85 , an album of live recordings by Bruce Springsteen (1986)
• 80–85 , a compilation album by Bad Religion (1991)
• Cupid & Psyche 85 , an album by band Scritti Politti (1985)
• 45/85 was a television documentary on World War II
• Minuscule 85, Papyrus 85, Lectionary 85 are early Greek manuscripts of the New Testament
• "85", a 2000 rap single by YoungBloodz, from their album Against Da Grain
• 85°C, a Taiwanese coffee store chain.

In sports

In U.S. college athletics, schools that are members of NCAA Division I are limited to providing athletic scholarships to a maximum of 85 football players in a given season. The specifics vary by the two Division I football subdivisions:

• In the top-level FBS, each player provided with a scholarship may, and almost always does, receive a full scholarship.
• In the second-level FCS, schools are allowed to provide football-related athletic aid equivalent to 63 full scholarships, but this aid may be divided among up to 85 players as the schools see fit.

In other fields

• The year AD 85, 85 BC, or 1985.
• The Muslim calendar year 85 AH.
• The atomic number of the chemical element astatine
• The number of the French department Vendée
• The ISBN Group Identifier for books published in Brazil
• The radix of the Ascii85 (sometimes called Base85) binary-to-text encoding
• The IQ and nickname of Aaron in Alien 3
• The number worn by Chad Ochocinco, whose name means "eight five" in Spanish
• Arabigere 85 is a village in India
• E85 fuel is 85% ethanol and 15% conventional gasoline
• MCS-85 was a family of Intel processors including the 8085
• TI-85 was a graphing pocket calculator by Texas Instruments
• KC 85 was a family of small computers built in East Germany in the 1980s
• PMD 85 was a personal computer built in Czechoslovakia in 1985
• Learjet 85 is an all-composite plane being developed by Bombardier Aerospace
• British Rail Class 85, a category of UK train locomotives
• DRG Class 85, a category of German train locomotives
• TK85 was a clone of the Sinclair ZX81 made in Brazil in 1983
• Lima Site 85 was a battle in the Vietnam War
• A85 is the Dutch Defence in the Encyclopaedia of Chess
• EF 85mm is a photographic camera lens by Canon
• F85 (disambiguation), multiple uses
• Part of the assignation for the Toyota AE85, commonly referred to as an "eight-five".
• KiHa 85 series is a diesel Limited express train that ran in Japan until 2023.
• HC85 series is the successor of KiHa 85 and is a hybrid diesel limited express train.

In military technology

• 85mm is a common caliber for cannons
• SU-85 was a Soviet tank
• TR-85 was a Romanian battle tank
• Tu-85 was a prototype Soviet bomber
• ASU-85 a Soviet self-propelled gun
• CZ 85 is a Czech 9mm semiautomatic pistol
• PT-85 is a Korean tank
• 7.62 Tkiv 85 is a Finnish army rifle
• HG 85 is a Swiss fragmentation grenade
• Taurus Model 85, a 9mm revolver made in Brazil

See also

• List of highways numbered 85
• List of highways numbered 85A
• Type 85 submachine gun

References

1. Sloane, N. J. A. (ed.). "SequenceA056809(Numbers k such that k, k+1 and k+2 are products of two primes)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
2. Sloane, N. J. A. (ed.). "SequenceA005900(Octahedral numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
3. Sloane, N. J. A. (ed.). "SequenceA005448(Centered triangular numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
4. Sloane, N. J. A. (ed.). "SequenceA001844(Centered square numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
5. Sloane, N. J. A. (ed.). "SequenceA001107(10-gonal (or decagonal) numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
6. Sloane, N. J. A. (ed.). "SequenceA007692(Numbers that are the sum of 2 non-zero squares in 2 or more ways)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.. The two smaller numbers on this list, 50 and 65, have 1 as one of the squares in their representations as sums of two squares.
7. Sloane, N. J. A. (ed.). "SequenceA006753(Smith numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.

External links

• 85
• Jorge Stolfi, The Hollywood Constant.